Consumer electronics devices often sense ambient temperature using temperature sensors that are partially hidden from view due to industrial design requirements for the devices and other aesthetic concerns. As a result, during operation, these devices heat up inside their housing cavities due to waste heat from the processor and other components operating within the device. This heat buildup within the housing causes the ambient temperature sensor inside the housing to read higher than expected temperatures, resulting in incorrect operation of applications and/or components that utilize the ambient temperature reading.
There are some devices that attempt to compensate for the temperature within the device cavity by algorithmically correcting for the likely higher temperature readings. This manner of correcting may bring the readings closer to the actual ambient temperature, but the algorithm makes assumptions about the effect of the heat within the housing that may not actually be the case at a given time.
In order to protect against over/under correcting, some devices have included additional temperature sensors within the device to provide more accurate inside temperature readings for inclusion in the algorithm that adjusts the ambient temperature readings provided to the processor.
In another method, an electronic device requires the isolation of the sensor from other internal components of the device and includes a large open port in the housing that allows outside air into the port. The sensor is situated within the housing cavity such that the sensor is exposed only to the outside air that enters the port. Industrial design considerations though often times do not allow for there to be open ports on electronic devices due to concerns with items entering in the ports that will cause damage to the electronic device, such as dust, moisture, etc. Also, product design and assembly often will not allow for the sensor to be completely shielded from the internal heat sources.
Another concern for open port systems is that the outside air may not actually flow through the port. In order to accommodate for this, some devices that use an open port have incorporated more than one open port on the device to increase circulation. The inclusion of additional open ports in the housing of a device increases the concerns discussed hereinabove.
Another method used in current electronic devices is to include the temperature sensor in a component that is isolated from the air inside of the device's housing. For example, the temperature sensor may be incorporated in a button that is located outside of the device's housing and, therefore, is exposed to the ambient air via the button. In this example, the effect of the temperature of the air inside the housing is minimal since the sensor is exposed primarily to the material of the button. This method requires the inclusion of an element of the device being outside of the device housing, which does not always meet industrial and/or product design concerns.